Radio frequency front end circuitry with improved primary transmit signal isolation
View Patent ↗RF front end circuitry includes primary transceiver circuitry associated with a primary antenna and secondary receiver circuitry associated with a secondary antenna. Generally, the primary transceiver circuitry and the primary antenna are located on one end of a mobile communications device, while the secondary receiver circuitry and the secondary antenna are located at an opposite end of the device. Cross-coupling connection lines run between the antenna switching circuitry for the primary antenna and the secondary antenna, and are reused to send a portion of primary RF transmit signals from the primary transceiver circuitry to the secondary receiver circuitry so that primary RF transmit signals coupled into the secondary receiver path via antenna-to-antenna coupling can be reduced.
1. Radio frequency (RF) front end circuitry comprising:
primary antenna switching circuitry coupled to a primary antenna node;
secondary antenna switching circuitry coupled to a secondary antenna node;
a first cross-coupling connection line and a second cross-coupling connection line coupled between the primary antenna switching circuitry and the secondary antenna switching circuitry;
primary transceiver circuitry coupled to the primary antenna switching circuitry;
secondary receiver circuitry coupled to the secondary antenna switching circuitry; and
switching control circuitry configured to operate the primary antenna switching circuitry and the secondary antenna switching circuitry such that:
in a first mode of operation, the primary transceiver circuitry is coupled to the primary antenna node, the secondary receiver circuitry is coupled to the secondary antenna node, and a portion of a primary RF transmit signal provided from the primary transceiver circuitry is provided to the secondary receiver circuitry via the first cross-coupling connection line; and
in a second mode of operation, the primary transceiver circuitry is coupled to the secondary antenna node via the first cross-coupling connection line, the secondary receiver circuitry is coupled to the primary antenna node via the second cross-coupling connection line, and a portion of a primary RF transmit signal provided from the primary transceiver circuitry is provided to the secondary receiver circuitry via the first cross-coupling connection line.
2. The RF front end circuitry of claim 1 wherein:
the primary transceiver circuitry is configured to provide primary RF transmit signals to the primary antenna switching circuitry and receive primary RF receive signals from the primary antenna switching circuitry; and
the secondary receiver circuitry is configured to receive secondary RF receive signals from the secondary antenna switching circuitry.
3. The RF front end circuitry of claim 2 wherein the secondary receiver circuitry is configured to cancel at least a portion of the primary RF transmit signals in the secondary RF receive signals due to antenna-to-antenna coupling based on the portion of the primary RF transmit signal.
4. The RF front end circuitry of claim 3 wherein:
in the first mode of operation, the portion of the primary RF transmit signal from the first transceiver circuitry is provided via a signal coupler in the primary antenna switching circuitry; and
in the second mode of operation, the portion of the primary RF transmit signal from the first transceiver circuitry is provided via a signal coupler in the secondary antenna switching circuitry.
5. The RF front end circuitry of claim 4 wherein the first cross-coupling connection line and the second cross-coupling connection line are shielded lines.
6. The RF front end circuitry of claim 5 wherein the first cross-coupling connection line and the second cross-coupling connection line are coaxial lines.
7. The RF front end circuitry of claim 4 further comprising a first antenna coupled to the primary antenna node, and a second antenna coupled to the secondary antenna node.
8. The RF front end circuitry of claim 7 wherein the first antenna and the primary transceiver circuitry are provided near a first end of a mobile communications device, and the second antenna and the secondary receiver circuitry are provided near a second end of the mobile communications device, which is opposite the first end.
9. The RF front end circuitry of claim 4 wherein the secondary RF receive signals are diversity multiple-input-multiple-output (MIMO) signals.
10. The RF front end circuitry of claim 3 wherein the first cross-coupling connection line and the second cross-coupling connection line are shielded lines.
11. The RF front end circuitry of claim 10 wherein the first cross-coupling connection line and the second cross-coupling connection line are coaxial lines.
12. The RF front end circuitry of claim 3 further comprising a primary antenna coupled to the primary antenna node, and a secondary antenna coupled to the secondary antenna node.
13. The RF front end circuitry of claim 12 wherein the primary antenna and the primary transceiver circuitry are provided near a first end of a mobile communications device, and the secondary antenna and the secondary receiver circuitry are provided near a second end of the mobile communications device, which is opposite the first end.
14. The RF front end circuitry of claim 3 wherein the secondary RF receive signals are diversity multiple-input-multiple-output (MIMO) signals.
15. The RF front end circuitry of claim 2 wherein the secondary RF receive signals are diversity multiple-input-multiple-output (MIMO) signals.
16. The RF front end circuitry of claim 1 wherein:
in the first mode of operation, the portion of the primary RF transmit signal from the first transceiver circuitry is provided via a signal coupler in the primary antenna switching circuitry; and
in the second mode of operation, the portion of the primary RF transmit signal from the first transceiver circuitry is provided via a signal coupler in the secondary antenna switching circuitry.
17. The RF front end circuitry of claim 16 wherein the first cross-coupling connection line and the second cross-coupling connection line are shielded lines.
18. The RF front end circuitry of claim 17 wherein the first cross-coupling connection line and the second cross-coupling connection line are coaxial lines.
19. The RF front end circuitry of claim 16 further comprising a primary antenna coupled to the primary antenna node, and a secondary antenna coupled to the secondary antenna node.
20. The RF front end circuitry of claim 19 wherein the primary antenna and the primary transceiver circuitry are provided near a first end of a mobile communications device, and the secondary antenna and the secondary receiver circuitry are provided near a second end of the mobile communications device, which is opposite the first end.